Composition for polishing surfaces composed of cellulose-ester compositions



Patented Nov; 6, 1928.

UNITED STATES PATENT OFFICE.

.TosErH E. HIRsH, or BROOKLYN, AND ARTH R :o. ROBSON, on NEW YoRK, N. 2., AS-

SIGNORSTO STANDARD VARNISH-WORKS, on NEW YORK, N. Y., A CORPORATION or NEW YORK.

COMPOSITION FOR romsnme SURFACES comrosnn on cELLULosE-ESTER COMPO- SITIONS.

No Drawing.

solvent and the lacquer coat is hardened by evaporation of the solvent after application. The lacquer may also contain pigments, as Well as gums and plasticizers for imparting special properties to the lacquer. These lacquers may be applied by different methods, such as dipping, brushing, spraying or fiowing. They are, however, very quick drying and cannot be worked to a smooth finish in the manner of ordinary paints, enamels or varnishes. Likewise, if the lacquer contains a pigment, it tends to dry to a relatively dull finish due to its thin nature. Moreover, where a series of successive coats of the lacquer are to be applied, spraying is commonly resorted to in order to minimize the effect of the solvent in the successive coats as they are applied upon the previously deposited lacquer composition and this method of application results in a roughened or finely pebbled surface. Unlike coating compositions which contain a drying oil and which harden or undergo a chemical change on exposure to the air in a relatively slow manner, such lacquers harden quickly by evaporation of the solvent and the cellulose nitrate component of such lacquer compositions undergoes no change upon evaporation of the solvent and will readily go into solution again if contacted with a solvent for too long a period. The application of such a lacquer coat to produce a high gloss has, due to the characteristics of lacquers of this class, neces sitated the use of a polishing operation to remove any roughness due to the methods of application employed and the drying charac- Application filed March 10, 1927. Serial No. 174,405.

teristics of the lacquer and to produce a finish ofhigh gloss and lustre.

The methods hitherto proposed for polishing such lacquered surfaces have involved the use of abrasives, usually applied together with an inert lubricating liquid such as water or paraflin oil. Such methods, however,

and polishing operation can be improved and greatly accelerated, and surfaces of excellent finish and high'lustre rapidly produced, by simultaneously subjecting the lacquered surface to a softening action and an abrasive action.

In the process of the present invention, accordingly, we carry out the polishing operation while treating the lacquered surface with a softening agent for the cellulose ester component of the lacquer composition. The polishing operation of the invention may be carried out with an abrasive, although for the production of a high gloss finish the abrasive action of a polishing pad or buifing wheel applied with pressure is frequently suflicient. The softening agent employed in carrying out the process of the invention may also have lubricating pro erties and may further promote the polis ing operation in this way; or a separate lubricant may also be used during the polishing operation.

We have further found 'it advantageous to employ a softening agent having a con trolled and restricted action upon the lacquer composition to prevent scarring or marring or misplacement of the lacquer coat during the olishing operation due to too great a softening or solvent action. For this purpose, we employ a mixtu'reineluding an inert diluent, or lubricant together with a softenin agent for the cellulose ester component of the lacquer composition. The softening effect of such a mixture can be closely regulated by adjusting the pro ortion of the softening agenti-to that of t e inert diluent or lubricant; while, atthe same time, where an inert lubricant is employed with the softening agent, lubrieating properties are also imparted to the polishing composition.

Various softening agents may be employed in carrying out the process of the present invention, and the softening agent used should be chosen to suit the nature of the surface bephosphate, acetone, and diacetone alcohol articuularly advantageaus for this purpose. thyl lactate, tri-acetin, glyceryl benzoate, benzyl benzoate, diethyl phthalate, phenyl phosphate, napthyl phosphate, ethyl methyl ketone, methyl alcohol, butyl alcohol, chloroform, chloral, diethyl ether, diphenyl ether and anisole are also useful as softeners of such lacquer compositions.

In combination or admixture with these softening agents we have found linseed oil, tung oil, soya bean oil, paraffin, kerosene, and beeswax to be advantageous as inert diluents or lubricants. Olive oil, cotton seed oil, peanut oil, lard oil, neatsfoot oil, menhaden oil, sperm oil, porpoise oil, crude petroleum, petroleum greases, glycerin, carnauba wax and Montan wax are also useful as diluents or lubricants. v

In treating lacquer finishes containing gums, the softening agent may also have a softening effect upon the gum component of the lacquer composition and may assist the polishing operation in this way. Iii the treatment of lacquer compositions including gum constituents, We have also found that the use of a polishing composition including benzol, toluol' or zylol is also advantageous, these aromatic hydrocarbons apparently further promoting the polishing action of the composition by such a softening effect upon the gum constituents of the lacquer composition. \Ve have also used turpentine as a diluent or a lubricant in the improved polishing composition of the invention, but we have found that it apparently also exerts asoftening action upon cellulose esters and that in some cases it can be employed as the softening agent in admixture with a suitable diluent or lubricant.

l/Vhile inert diluents or lubricants of the dif ferent types described are all more or less useful in carrying out the process of the invention, certain of these materials have properties which render them better suited for use in this connection than others. A softening agent and a diluent or lubricant which are mutually immiscible may be employed together by emulsifying the mixture or otherwise dispersing the softening agent through the diluent or lubricant, but we have found it advantageous to use a diluent or lubricant which will dissolve the softening agent employed. Likewise, by using a diluent or lubricant which is substantially non-volatile at ordinary temperatures, the action of the pol ishing composition is rendered more uniform and it may be used without special precautions to take care of vaporized constituents; and if a; volatile softening agent is employed such a non-volatile diluent or lubricant also assists in inhibiting vaporization of the softening agent. The viscous or oily or waxy diluents are especially valuable due to their lubricating properties and the use of compositions including diluents of this character contributes to the smoothness and gloss of the finish obtained. We have also found it useful to employ diluents or lubricants which are substantially immiscible with water.

In addition to the mixtures describedabove, there are some natural mixtures and crude products which combine a softening action and a diluting and lubricating action, probably due to the presenceof different constituents contributing these different properties to the mixture, which may be employed directly in carrying out the process of the invention. We have found, for example, that the conifer oils boiling above turpentine may be employed in the. treatment of cellulose nitrate containing lacquer compositions. In particular, we have found a pine oil having a specific gravity between about 0.900 and 0.925 and about 50% distilling off between about 200 to 215 C. to be specially advantageous for polishing surfaces composed of cellulose nitrate in accordance with this invention. Other natural mixtures which are useful in carrying out the process of the invention are camphor oil, cedar oil and lemon-grass oil.

Any of the ordinary abrasives, in a suitable state of division, may be used, such as sand, pumice, tripoli, carborundum or rotten stone. These abrasives are used 'in a finely divided state and the-grade of the abrasive can be chosen to suit the finish desired, that is a finer abrasive is employed for a smoother and higher gloss finish, in the usual way. These abrasives may be applied to the surface to be polished in connection with paper, felt, cloth or fibre pads, blocks or wheels or similar polishing means, or in the form of prepared sand paper, emery paper, emery cloth, or the like in which the abrasive is fixed to a backing material. In polishing to get a high lustre, such abrasives can in some cases be dispensed'with, and the abrasive action of the polishing means alone can be relied upon. It will be apparent that progressively finer sive or without any abrasive other than the action of the polishing or buffing means.

The composition of the polishing com.-

. pound is adjusted in accordance with the of finely powdered pumice stone.

character of the finish desired and the char-- acter of polishing operation, and also with reference to the composition of the lacquer being polished. In gen'eral a polishlng com pound including a diluent or a lubricant-1n predominating amount is employed. For example, forpolishing a surface lacquered with a lacquer comprising 90' parts of pure cellulose nitrate and 10 parts of pigment, we have used a mixture containing 55 parts of linseed oil and 4.5 parts of commercial ethyl acetate (85%) together with an equal weight For polishing a surface lacquered with a lacquer composed of 100 parts cellulose nltrate, 20 parts of pigment, 40 parts oftricresyl phosphate and 20 parts of ester gum we have used a mixture containing=85 parts of linseed oil, 15 parts of commercial ethyl acetate and about an equal weight of powdered pumice. The process of the invention is useful for .j. polishing both clear and pigmented lacquer finishes. Y D

The polishing operatlon may be carried out in different ways. For example, the lacquered surface may be rubbed with a pad which is wet with a mixture of the softening agent and diluent or lubricant and then dip ed in the abrasive before it is applied, or t e polishing means may be supplied with the polishing composition in the form 0f a paste or suspension. The polishing compo- .sition may be removed as the polishing. op-' -eration progresses, or the composition may be allowed to dry on the lacquered surface and subsequently removed and the surface subjected to a further finishin' polish. The polishing o eration may also be carried out g or polishing wheel to which the operatiomcon'cluded with a dry buffing or polishing wheel.

The usual polishing methods can; in general, be used, although when carried out in accordance with thepresent invention-the amount-of time required may be materially reduced. Following the polishing operation, the surface may be J mobile cc waxed if desired in much the usual way.

The composition ofthe presentinvention is of special value and application in finishing lacqgiered metallic sur 'odies and parts and the like. While the present inventionhas; been deaces, such as autoscribed particularlyf in"connection with the treatment of cellulose mum lacquer fin ishes, it will be apparent thatit mayalso be applied to smoothing, levelling and polishing lacquer finishes containing other cellulose or cellulose acetate masses-or the like. One

method of treating small articles ofthis na- Such objects may include sheets,

ture is to tumble them in a drum together with the polishing composition of the invention. For example, small celluloid articles may be introduced into a drum containing an equal weight of sawdust to which has been added A. of its weight of a paste containing 35 parts of tung oil, 15 parts of ethyl acetate and an equal weight of finely powdered pumice, the drum rotated for 15 minutes, the contents discharged and separated from the sawdust, and tumbled againfor another 15 minutes with clean sawdust.

We claim: a

1. An improved levelling, smoothing,-and

polishing composition comprising a cellulose ester softening agent, an inert diluent or lubricant, and an abrasive.

2. An improved levelling, smoothing, and polishin composition comprising a cellulose ester so tenin agent, an inert substantially non-volatile iluent, or lubricant, and an abrasive. I

, 3. An improved levelling, smoothing, and polishing composition comprising a cellulose ester softening agent, and an inert substantially non-volatile diluentor lubricant.

4. An improved levelling, smoothing, and I polishing composition comprising a cellulose ester softening agent, an abrasive, anda predominating amount of an inert dilfient or rlubricant. w

5. An improved levelling, smoothing, and

polishin composition comprising a cellulose ester so ening' agent, and a predominating amount of an lnert substantially non-volatile diluent or lubricant.

In testimony whereofJ aflix my signature.

. v JOSEPH E. HIRSH. In testimony whereof I aflix my signature.

. ARTHUR nnorson. 

